1. Field of the Invention
The invention relates to a cooling structure of an electronic equipment such as substrate units and so forth, which needs forced-air-cooling by fans and so forth, more particularly to a cooling structure of the substrate units, for example, installed in a large server, a disc array unit and so forth, to a cooling structure of other electronic equipment, and to an information processing equipment provided with the cooling structure.
2. Description of the Related Art
With an information processing equipment such as a large server, disk array unit and so forth, a forced-air-cooling structure by use of fans and so forth is employed, for example, as shown in FIGS. 1, 2, 3 and 4. FIG. 1 is an exploded perspective view of the cooling structure, FIG. 2 is an external view as viewed from a front face side of the information processing equipment, FIG. 3 is an external view as viewed from a back face side of the information processing equipment, and FIG. 4 shows a sectional structure of the cooling structure.
There is provided, for example, a rectangular parallelepiped housing 2 in the information processing equipment, wherein a front shelf 4 is provided at the front side of the housing 2 and a back shelf 6 is provided at the back side thereof. A plurality of substrate units 12 are detachably attached to substrate housing parts 8 which are individually installed in the shelves 4, 6, respectively wherein the respective substrate housing parts 8 are partitioned back and forth by a back panel 14. A plurality of fan units 16 are provided at the lower side of the respective substrate housing parts 8, and there is provided an intake duct 18, which is shared by the front shelf 4 and the back shelf 6, at the upstream side of these fan units 16. An intake part 20 is installed at the front shell 4 side in the intake duct 18. A plurality of fan units 22 are provided at the upper side of each substrate housing part 8, and an exhaust duct 24 which is shard by the front shelf 4 and back shelf 6 is formed at the downstream side of the fan units 22, wherein an exhaust port 26 is installed at the back shelf 6 side in the exhaust duct 24.
With the information processing equipment, if the fans 28 of the fan units 16, 22 are rotated, for example, as shown in FIG. 4, air for cooling W is sucked from the intake port 20 into the intake duct 18, and passes through the respective substrate housing parts 8, and it is guided into the exhaust duct 24, then exhausted from the exhaust port 26. Accordingly, the substrate units 12 housed in the respective substrate housing parts 8 are cooled by the passing air for cooling W.
For such a forced-air-cooling structure, there is, for example, JP-A 2002-32148 as a prior art.
JP-A 2002-32148 discloses a cooling structure, as shown in FIG. 2 and the explanation thereof, wherein air is guided from a lower side of a front panel side into a housing by the rotation of cooling fans provided at the upper side of a back panel, and the air is also guided from a vent provided on the substrate in the housing into the upper side of the housing.
The information processing equipment as shown in FIGS. 1 to 4 has a structure that the back panel 14 and the substrate units 12 are respectively perpendicularly arranged and the fans 28 are provided at the upper side and the lower side thereof, wherein air is blown perpendicularly to effect cooling, and such a cooling structure is generally employed. With such a cooling structure, in the case of a rack mount unit (assuming that units are mounted on a standard rack such as 19 inch rack), it is unclear what kind of units are installed in a vertical direction so that it is not appropriate to provide the intake port 20 or the exhaust port 26 in the vertical direction to secure a space where the units are provided. With such a requirement, a space for forming the intake duct 18 and the exhaust duct 24 is needed.
Each space between the substrate units 12 and the fans 28 has an intimate relation relative to a cooling effect of the substrate units 12, and if a sufficient space is not secured between the substrate units 12 and the fans 28, the flow of the passing air for cooling W is blocked so that air velocity is prominently biased depending on the position of each substrate unit 12.
Accordingly, the cooling structure having the fans 28 at the upper and lower sides of the substrate housing parts 8 wastes a space in which the fans 28 are installed, and requires a space (chamber) in the intake duct 18 and the exhaust duct 24 for restraining air velocity from being biased between the substrate units 12. If such a space is secured, the space lowers a mounting efficiency of the substrate units 12 and so forth in the direction of the height of the housing 2.
Meanwhile, each fan 28 has the structure, for example, as shown in FIG. 5, wherein a motor 34 is attached to each rotary axis of rotary blades 32. According to such an axial-flow fan, the volume of air is small at the central portion of the blades 32, but becomes large as the position is far from the central portion in the radial direction. That is, the characteristic of the axial-flow fan is small in air velocity at the central side area A, and large in velocity at an outer edge side area B. Accordingly, the air velocity is prominently biased between the central portion and the outer edge portion of the blades 32 in the vicinity of the fan 28, and hence it is inevitable to secure a space at the intake side of the fan 28 to prevent the air velocity from being biased.
The problem to improve a mounting efficiency while restraining the biasing of the air velocity is not disclosed in JP-A 2002-32148, and such a problem cannot be resolved even if the technique disclosed in JP-A 2002-32148 is referred to.